It has to be one of the finest addresses in the country. And with a rent tag of �115 a week, it is, to borrow from estate agent parlance, "a bit of a steal".

The property in question, a seven-bedroom apartment within Kensington Palace, is home to the Queen's cousin Prince Michael of Kent and his wife.

Princess Michael of Kent with Fredrick and Gabriella

But now their tenure has been called into question, and by no other authority than Conservative MP Edward Leigh, the chairman of the Public Accounts Committee.

On Thursday the committee visited the London palace where a number of "fringe" royals live in "grace and favour" apartments.

Speaking on BBC Radio 4 before the visit, Mr Leigh warned that over the next year or two, a hint may be dropped at a "polite tea-party" that the time had come for them to move on.

Prince and Princess Michael of Kent were handed keys to their apartment in the palace by the Queen, shortly after the pair married in 1979.

Their grown-up children, Lord Frederick Windsor and Lady Gabriella Windsor, also have use of the property.

Second home

The couple, who own a �3.5m home in the country, contribute �6,000 a year - about �115 a week - towards the upkeep of the palace, which used to also be home to Diana, Princess of Wales.

Princess Alice lives with her children and grandchild

On the open market, this "peppercorn" rent would barely cover the cost of a broom cupboard in such an exclusive and sought-after neighbourhood.

One local estate agent is currently asking �2,950 a week for a five-bedroom apartment in nearby Kensington Gore.

And while that looks like a delightful property, it cannot rival the palace's unique setting, on the edge of Kensington Gardens, with its views across to Hyde Park.

But the Prince and Princess are not alone in making a home within the palace, which has been a favourite royal residence since 1760.

Staff benefits

Other "tenants" include the Duke and Duchess of Kent, 100-year-old Princess Alice, her son and daughter-in-law, the Duke and Duchess of Gloucester, and, periodically, their grown up children the Earl of Ulster, Lady Davina Windsor and Lady Rose Windsor.

Princess Margaret was among those living there

Until her death at the start of the year, Kensington Palace was also a home to the Queen's sister, Princess Margaret. Her son, Viscount Linley moved into the apartment two years ago to be close to his mother during her sickness.

The viscount, his wife and young daughter are due to move out soon, and into a private residence.

And not everyone living at the palace enjoys such beneficial terms of residence.

Royal household staff who are based at the palace pay 16.7% of their salary in rent and others, such as Sir Michael Peat, keeper of the privy purse, pays �45,000 a year for his accommodation.